1. Field of the Invention
The present invention relates to apparatuses and methods for recording/reproducing on/from a medium, and in particular relates to a defect management method in a recording/reproducing apparatus using areas used for defect management process on a medium.
2. Description of the Related Art
Today, recording/reproducing apparatuses are known which irradiate an optical disc-like recording medium represented by a CD-R/RW (CD Recordable/Rewritable), a DVD±R/RW (DVD±Recordable/Rewritable Disc), a DVD-RAM (DVD-Random Access Memory), a Blu-ray Disc (registered trademark, hereinafter referred to as a BD) and the like, with a laser beam using a semiconductor laser to record data. In the rewritable or write-once optical disc medium, a defective portion on the medium occurs due to a flaw caused by partial damage of the medium, fingerprint, dirt, degradation of a recording film, etc., and accordingly, even if data is recorded on the defective portion, the data is most likely to be unable to be read. As one of the methods that extend the life of the disc by avoiding such a defect on the disc face, there is a defect management method called “linear replacement” that instead of recording the data on the defective portion, records the data in a replacement area (alternate recording area) on the same optical disc. This method is already applied to the DVD-RAM, which is described in pp. 29-31 of “DVD-RAM technology” edited by TRICEPS Planning Department, published by TRICEPS Corp., 2000. This technology has been already applied to the BD as well, wherein during recording in a unit of a cluster in a user data area, a cluster unsuccessful in recording or one successful in recording but unsuccessful in verifying is recorded in the replacement area on the disc. Note that a cluster corresponds to a unit of the minimum recording block in the present invention. Then, address information of a detected defective cluster and address information of the cluster recorded in the replacement area are registered as a defect list (DFL) in a management area on the disc. Several types of DFLs are also defined, and as this example, a defective area is registered as a Re-Allocated Defect (RAD) type when the defective area has only one defective cluster, while the defective area is registered as a Contiguous Re-allocated Defect (CRD) type when the defective area has two or more consecutive clusters. For example, when a defective area has ten consecutive clusters, ten DFL registrations are required to register the defective area as the RAD type. However, only two DFL registrations are required to register the defective area as the CRD type and the number of DFL registrations in the management area can be reduced. This is described in JP-A-2008-510263. Reading this DFL during reproduction makes it possible to read a replacement cluster recorded in the replacement area instead of reading a cluster designated by a recording command from a host.
Moreover, JP-A-08-050766 discloses as follows:
when a defective cluster occurs in the user data area on a recording medium, a replacement cluster is searched in a replacement area closest to this defective cluster, and it is then determined whether or not the searched replacement cluster has any space to record the cluster. If it has, the access distance to the replacement cluster is reduced by performing the defect management process in this replacement area, and the defect management process is performed efficiently.